Weather Blog

A foot of rain in Seattle in 30 days? That's....not that rare

A foot of rain in Seattle in 30 days? That's....not that rare
A rainy window pane on a stormy day in Seattle. (Photo courtesy: Michael Mclaughlin Photography

I was surprised when I calculated the numbers -- Seattle received just over a foot of rain in the 30 days from Feb. 8 through March 10, coming in at 12.01 inches.

A foot of rain? Even in soggy Seattle, that seemed pretty wet, especially since we only average about 37 inches of rain per year.

I knew it wouldn't be a record -- November 2006 had 15.63" of rain. But I figured it had to be near the top?

So I asked National Weather Service Seattle climate guru Dana Felton where that 30-day stretch of rain ranked among the wettest in Sea-Tac History (1945).

It had to be top 10? Top 5?

Nope.

Top 25?

No.

The answer?

57th.

Now this is a bit of a strange list because a few wet patterns that have extended beyond 30 days take up multiple spots on the list, just by shifting the 30 day period a few days forward or backward here and there. For example, the top 14 slots on the list are some variation of a 30 day period with November 2006 embedded somewhere in the time frame.

The first non-2006 entry is at No. 15 -- 12.95 inches ending on March 12, 1972. Other years that have had wetter patterns and multiple entries include 1998, 1953, 1951, 1979 and a single entry in 1990 and 1959.

However, Felton says that this is only the second period in Sea-Tac history where we've had such a 30-day wet streak span February into March (five of the 56 entries ahead of this year included dates in March 1972.)

The record wettest time frame is 15.82" from Oct. 29 through Nov. 27, 2006.

How far will this month climb the ladder of wettest March on record?

We're also watching a more traditional -- and much easier to track -- record for wettest March at Sea-Tac Airport. As it stands right now, we've got a ways to go despite the very soggy start to the month. Sea-Tac is at 5.98" of rain this month -- good for 9th wettest on record so far.

Here is the list:

1. 8.40" -- 1950
2. 8.15" -- 1997
3. 7.20" -- 2012
4. 7.12" -- 1971
5. 6.74" -- 1972
6. 6.34" -- 2003
7. 6.29" -- 2011
8. 6.26" -- 1957
9. 5.98" -- 2014

Forecasts indicate at least two more solid batches of rain coming in on Friday and Sunday so we'll move up the list for sure. 2.42 inches is a tall order so I'm not sure we'll make it to the top, but Top 5 looks doable. What's interesting is this will be the third time in the last four years Seattle has had a very soggy March!